| 摘要 |
PURPOSE:To attain voice callout, by providing a control circuit which increases the gain of a reception amplifier of a station to be called, at callout more than at communication. CONSTITUTION:In calling an interphone T3 from an interphone T1, a call signal is applied to the interphone T3 through a signal line 2, a control circuit 5 is turned on, a Gain Control circuit 6 is operative, the Gain of a reception amplifier 9 is increased and voice callout is done at a speaker 11. |
